The fully kinetic Biermann battery and associated generation of pressure anisotropy

The dynamical evolution of a fully kinetic, collisionless system with imposed background density and temperature gradients is investigated analytically. The temperature gradient leads to the generation of temperature anisotropy, with the temperature along the gradient becoming larger than that in the direction perpendicular to it. This causes the system to become unstable to pressure anisotropy driven instabilities, dominantly to electron Weibel. When both density and temperature gradients are present and non-parallel to each other, we obtain a Biermann-like linear in time magnetic field growth. Accompanying particle in cell numerical simulations are shown to confirm our analytical results.Comment: 5 pages, 2 figures, + Supplementary materials (4 pages, 2 figures

Measuring the Photon Energy Scale through Test Beam Data

This dissertation aims at measuring the photon energy scale combining specialized Monte Carlo simulation with data taken during the combined ATLAS test beam in 2004. This work explains the steps taken to arrive at the photon energy scale, starting from the knowl- edge acquired for electrons. The chapters are structured as follows: Chapters 1 and 2 briefly introduce this work and the motivation behind it. Chapter 3 gives an overview of the LHC ex- periment and the ATLAS detector as a whole. Chapters 4 and 5 address in detail the ATLAS electromagnetic calorimeter and signal reconstruction at the cell level. Chapter 6 concentrates on the setup for the combined test beam with emphasis on the photon run. Chapter 7 details the event selection strategy used for the photon run analysis. Chapter 8 describes the generation and tuning of the special Monte Carlo for the photon run. Chapter 9 focuses on the highly special- ized Monte Carlo studies that employed special calibration objects known as calibration hits. Chapter 10 details the methodology behind the measurement of the photon scale and evaluates it in terms of the electromagnetic calorimeter resolution. Chapters 11 and 12 present a summary of the results and the conclusions, respectively

REPUTATION AND STATE COMMODITY PROMOTION: THE CASE OF WASHINGTON APPLES

A dynamic multiple-indicator multiple-cause (MIMIC) framework was used to estimate the latent variable reputation with price premiums for Washington apples and attributes that covered the period July 1996 to November 1999. A maximum likelihood two-stage approach was employed. For comparison purposes, a hedonic regression was also estimated. Results from the first stage of the estimation procedure in the MIMIC reputation model suggest that price premiums are good indicators of reputation. The indicator coefficients, also called factor loadings, imply that the estimated reputation variable is common to the five indicators chosen and that the measurement of reputation is not likely to be obscured by a wide diversity in the indicators. The common factor issue suggests a possible existence of collective 'Washington' reputation. Results from the second stage of the MIMIC reputation model are compared to those from the Hedonic proxy model. In general, results from the MIMIC reputation model make more intuitive sense and are in line with the theoretical literature on reputation than the results from the Hedonic proxy model. Reputation is found to be stationary and that shocks to Washington's reputation are temporary. In the MIMIC reputation model, all the estimated coefficients on the explanatory cause variables had positive signs, except the Red Delicious variety variable. The magnitude of the coefficient on the logo term is large, suggesting a strong impact on reputation. The estimated constant term in the MIMIC reputation model is negative and relatively large, which suggests that reputation is declining. The concerns of declining perceived "eating" quality in Washington varieties thus appear to be real. It appears then that the apple industry is currently benefiting from past/accrued reputation. The current standards in the apple industry give room for some Washington producers to free ride on the collective reputation. Hence, there may be some justification for minimum quality standards. For efficient public policy purposes, our findings suggest that policymakers and the apple industry as a whole should consider reputation in their cost-benefit analysis for purposes of resource allocation.Marketing,

Magnetic reconnection and stochastic plasmoid chains in high-Lundquist-number plasmas

A numerical study of magnetic reconnection in the large-Lundquist-number ($S$), plasmoid-dominated regime is carried out for $S$ up to $10^7$. The theoretical model of Uzdensky {\it et al.} [Phys. Rev. Lett. {\bf 105}, 235002 (2010)] is confirmed and partially amended. The normalized reconnection rate is \normEeff\sim 0.02 independently of $S$ for $S\gg10^4$. The plasmoid flux ($\Psi$) and half-width ($w_x$) distribution functions scale as $f(\Psi)\sim \Psi^{-2}$ and $f(w_x)\sim w_x^{-2}$. The joint distribution of $\Psi$ and $w_x$ shows that plasmoids populate a triangular region $w_x\gtrsim\Psi/B_0$, where $B_0$ is the reconnecting field. It is argued that this feature is due to plasmoid coalescence. Macroscopic "monster" plasmoids with $w_x\sim 10$% of the system size are shown to emerge in just a few Alfv\'en times, independently of $S$, suggesting that large disruptive events are an inevitable feature of large-$S$ reconnection.Comment: 5 pages, 6 figures, submitted for publicatio

Fast magnetic reconnection in the plasmoid-dominated regime

A conceptual model of resistive magnetic reconnection via a stochastic plasmoid chain is proposed. The global reconnection rate is shown to be independent of the Lundquist number. The distribution of fluxes in the plasmoids is shown to be an inverse square law. It is argued that there is a finite probability of emergence of abnormally large plasmoids, which can disrupt the chain (and may be responsible for observable large abrupt events in solar flares and sawtooth crashes). A criterion for the transition from magnetohydrodynamic to collisionless regime is provided.Comment: 4 pages, 1 figur

Geometrical properties of Potts model during the coarsening regime

We study the dynamic evolution of geometric structures in a poly-degenerate system represented by a $q$-state Potts model with non-conserved order parameter that is quenched from its disordered into its ordered phase. The numerical results obtained with Monte Carlo simulations show a strong relation between the statistical properties of hull perimeters in the initial state and during coarsening: the statistics and morphology of the structures that are larger than the averaged ones are those of the initial state while the ones of small structures are determined by the curvature driven dynamic process. We link the hull properties to the ones of the areas they enclose. We analyze the linear von-Neumann--Mullins law, both for individual domains and on the average, concluding that its validity, for the later case, is limited to domains with number of sides around 6, while presenting stronger violations in the former case.Comment: 12 page

Luxury brands on Instagram: A netnographic approach

The present research concerns a netnography study from June 1st 2020 to January 1st 2021on Instagram communication of six luxury brands: Louis Vuitton, Prada, Gucci, Dior, Chanel and Burberry. Five variables were taken into consideration: number of followers, number of posts, average comments, average likes and engagement rate. This qualitative study reflects the impact of digital transformation on the luxury market. Overall, results demonstrate luxury brands similarities in their Instagram communication strategy - Louis Vuitton and Gucci; Dior and Chanel; Prada and Burberry. With our findings, we were able to associate these luxury brands with the core dimensions of brand coolness. Implications of these findings are discussed with future research directions suggested.info:eu-repo/semantics/publishedVersio

Extensive Analysis of a Real-Time Dense Wired Sensor Network Based on Traffic Shaping

XDense is a novel wired 2D mesh grid sensor network system for application scenarios that benefit from densely deployed sensing (e.g., thousands of sensors per square meter). It was conceived for cyber-physical systems that require real-time sensing and actuation, like active flow control on aircraft wing surfaces. XDense communication and distributed processing capabilities are designed to enable complex feature extraction within bounded time and in a responsive manner. In this article, we tackle the issue of deterministic behavior of XDense. We present a methodology that uses traffic-shaping heuristics to guarantee bounded communication delays and the fulfillment of memory requirements. We evaluate the model for varied network configurations and workload, and present a comparative performance analysis in terms of link utilization, queue size, and execution time. With the proposed traffic-shaping heuristics, we endow XDense with the capabilities required for real-time applications